An important aspect of motor vehicle engine control concerns proper positioning of a number of valves which control or regulate the passage of a compressible medium. For example, an exhaust gas recirculation valve is controlled to return a desired amount of exhaust gas to the intake air stream for emission control purposes.
A common approach utilized to control such valves is to specify a valve position in terms of various input parameters, based on extensive empirical testing and calibration. However, this approach is very time consuming and inefficient, and needs to be repeated or revised for each new powertrain configuration, or each change in an existing powertrain configuration. Furthermore, the trend in engine control is to develop model-based commands that take engine and vehicle dynamics into account, and the control methodology described above is not well suited to a model-based approach. Accordingly, what is needed is an improved control methodology that requires less calibration effort, that is less sensitive to changes in powertrain configuration, and that is more amenable to a model-based control approach.